(1) Field of the Invention
The invention relates to an electric motor comprising a permanent magnet rotor, which is supported rotationally about a central axis, a wound stator having a cylinder ring-shaped stator winding, claw poles, which are disposed perpendicularly to ring disc-shaped stator plates and around the central axis, and a cylinder jacket-shaped yoke ring, the length of the claw poles in the axially parallel direction being clearly greater than half the inner diameter of the stator.
(2) Description of the Related Art
The most common manner of producing claw pole stators consists in bending off the pre-punched claws from the center of a disc perpendicularly thereto. In this manner the maximum length of the claws in the axial direction is limited to approx. half the inner diameter of the stator. The achievable power of such motors is therefore limited and it is sometimes necessary to arrange a plurality of stators in succession.
An electric motor of the generic kind is disclosed in US 2002/0180302 A1. In the electric motor disclosed, the stator is composed of four components. The claw poles are punched out from lamellar sheet metals, and then bent to form a ring, the ends of which are connected to one another. Two of these bent claw pole sheet metals are then mounted together with two other stator sheet parts. This method is relatively cumbersome and unreliable. The large number of joints further increases the magnetic resistance and thereby reduces the efficiency of the motor.